1. Field of the Invention
The present invention relates to fuel injection pump operating condition detectors, and more particularly to a fuel injection pump operating condition detector suitable for use in a distributor type fuel injection pump in a diesel engine mounted on a motor car, wherein fuel is pressure fed by a reciprocating plunger.
2. Description of the Prior Art
Recently, diesel engines have been mounted on not only large-sized vehicles such as trucks but also passenger motor cars and the like based on the economics in fuel consumption thereof. Consequently, there has been voiced for necessity of providing tachometers for detecting the rotation speed of the diesel engines. However, the conventional diesel engines have no ignitors unlike the gasoline engines, and hence, electric tachometers cannot be operated by electrical wirings, so that the rotation speed of engines are taken out by wires and the like to move mechanical tachometers. From the abovedescribed reasons, the rotation speed take-out portion is complex in construction, oil leakage may be caused, and the arrangement of wires may be restricted. Furthermore, there has not been any means for easily measuring a fuel injection timing. Consequently, heretofore, there have been such disadvantages that the set condition of the fuel injection pump cannot be finely adjusted at the time of assembling the engine, hence, only such a measure is taken as to match coincidence marks provided on the engine body and the injection pump body are mechanically matched, in order to perform the fine adjustment, it is necessary to remove the plunger portion of the fuel injection pump and verify the fuel injection by visual inspection, and, the adjustment cannot be performed during running condition of the engine.
There have been proposed to detect the running condition of the engine such methods being similar to the methods of sensing the running condition of machines in general that reflection marks such as light reflecting sheets are attached to rotatable parts including a flywheel, crankshaft, camshaft and crankwheel for example, the light is emitted to the abovedescribed parts and pulses of the reflected light are detected by photo-transistors and the like and counted, or metallic ridges or grooves are formed on the rotatable parts and the changes in magnetic flux are detected therefrom and counted. However, the abovedescribed methods have been improper when an engine room space is excessively limited as with a vehicle-mounted engine or when simplified performance inspections are performed as on an engine production line.